Cisco NAT

I'm having a little trouble configuring a static nat in my 1600 Series router. I have several ports forwarded to specific equipment from the Serial interface:
i.e. ip nat inside source static tcp 192.168.1.10 23 interface Serial0 23
However, I would like to only forward that port when it originates from a specific Internet IP of 68.10.101.54. I have tried substituting that 68.10.101.54 for the interface, but when I do the port doesn't forward properly. The router does accept the command, though; so I must be missing something. Any ideas?

It sounds like you want to use NAT and route maps to accomplish your goal.
The attached link contains how to set this up. In the example, their
access-lists use ip, but you could set it up for specific ports using tcp
and specifying the ports in the access-list. That should achieve your
desired results if I'm reading your question properly.
http://www.cisco.com/en/US/docs/ios/12_2t/12_2t4/f eature/guide/ftnatrt.htmlHTH,
Don